Stack ST670 User Information page 2

STACK ST670 User Information
INSTALLATION
This sensor, when used for measuring vehicle speed, is best fitted to an undriven
outside 1 wheel. The sensor produces pulses, which are then used to calculate the
vehicle speed. The sensor is triggered by a number of 'Targets' (See Sensor
Targets). It is essential to ensure that these devices are NOT mounted in a position
close to any devices, or associated wiring, which are likely to interfere with the correct
operation of the sensor.
Suggested Wiring Clearances
Ignition HT & coil leads
Radio transmitters and aerial leads
Fast switching inductive loads like fuel
injectors, hydraulic solenoids.
Any powerful source of heat
The ST670 connects into a STACK system via a four way, ITT Cannon Mini Sure
Seal (MSS) connector. The following polarity is observed in all cases:
= Pin
= Socket
These terminals must be connected to the corresponding terminals of the selected
input channel.
Pin Number
1
2
3
4
The ST670 must therefore, be connected to WS/P2/P3 on a ST872 harness: P2/P3
on a ST875: C1 to Cx on any ST883 harnesses: or WS on a ST892 harness.
Sensor Targets.
The targets can be any suitable metallic object, which passes within range of the
sensor tip. Iron or mild steel targets are preferred as they give a stronger signal to the
sensor whilst aluminium, brass or copper targets give approximate one third of the
range.
1 The outside wheel is on the left for clockwise, and on the right for anti-clockwise
circuits.
ST541015-005
Min space ST670
100mm (4")
75mm (3")
75mm (3")
Shield with reflective material
Plug Socket
Harness End Sensor End
2 1 1 2
3 4 4 3
Signal Description
Signal from sensor
No connection
No connection
0v
1
It is IMPORTANT that the sensor and targets should be rigidly mounted so they do
not move with vibration. Targets should be at least 10mm (5/8") diameter and stand
4mm (5/32") proud (Fig.1). Smaller targets can be used but this will reduce the range.
Small aluminium, brass or copper targets will generally NOT work.
Nothing other than the targets should come within 6mm (1/4") of the end of the
sensor. If the sensor mounting position is to be recessed, then a hollow of 24mm
(15/16") diameter and at least 4mm (5/32") deep should be allowed around the sensor
(Fig 2).
24 min
4 (5/32) min
(15/16)
10 min
(3/8)
1.5 (60thou)
Fig. 1
Sensor Adjustment.
1. Connect the sensor to the system and turn on the power.
2. Assemble the first (rear) nut onto the sensor.
3. Insert the sensor into the mounting bracket hole and fit the front nut.
4. Rotate the wheel and move the sensor slowly forward by undoing the rear nut
counter-clockwise until the light comes on for every target.
5. Undo the rear nut half a turn more.
6. Without rotating the sensor or rear nut, finger-tighten the front nut.
7.
Tighten the rear nut with a 13mm AF spanner. Do NOT let the sensor rotate.
Do not over-tighten – half a flat of the nut should be sufficient.
The sensor has an in-built light (LED) which can be used to check that both the
mechanical and electrical installations have been performed correctly. This light
should be ON when a target is in front of the sensor.
Checks for correct installation and adjustment
1. Rotate the wheel and check that the light comes on for each target and goes off
between each target.
2. Check that both the sensor and targets are rigidly mounted.
3. Check that the front nut does not cover any part of the sensing end.
4. IMPORTANT Check the gap between sensor and any of the targets is NOT less
than 0.5mm (20thou). so there is no risk of the sensor touching targets in
operation.
Please see the user manual of your system for setting the wheel circumference
and pulses per revolution.
ST541015-005
Dimensions in mm (in)
8 8
6
(1/4) (5/16) (5/16)
4
(5/32)
Fig. 2
2